Low-cost solution-processable organic thin-film transistors for (bio)sensing applications

We report on low-operating voltage organic field-effect transistor (OTFT) devices, which can be used as sensors in electrolytes and liquid media, using biofunctionalized, biocompatible, organic semiconducting layers. OTFT-based sensing technologies take advantage of the physical or chemical changes taking place in or around the organic semiconducting material when exposed to different analytes in gaseous or aqueous environments. Measurements in electrolytes and complex media relevant for cell analysis have shown that the devices can be directly used as ion-sensitive transducers and are suitable for in vitro biosensing applications. Within the pH range from 6-8 relevant for cell analysis, an almost linear dependence of the device current with the pH has been observed. At room-temperature, ion-sensitivity of e.g. Na⁺ down to 10^-5 M can be easily achieved.